I know a friendship is changing when I stop feeling relaxed before replying

Dear Delyara, I used to message her easily. I didn’t think too much. I was warm naturally. Now I find myself checking the tone, reducing what I say, wondering how much to share, whether I’m being too much, whether she still wants the same closeness I do. That kind of change is painful because it often happens quietly. No argument, no betrayal, no one clear moment. Just a slow movement from ease into caution. And once caution enters friendship, something important has already gone.